Thermo-expansion meter.



G D. BABGOCKL THERMO EXPANSION METER.

APPLICATION FILED mm 21. 1909.

926,536, Patented June 29, 1909.

wit memes I Momma UNITED STATES PATENT OFFICE.

CLIFFORD D. BABOOOK, OF NEW YORK, N. Y., ASSIGNOR TO THE UN lTED WIRELESS TELE- GRAPH 00., OF NEW YORK, N. Y., A CORPORATION OF MAINE.

THERMO-EXPANSION METER.

To all whom it may concern:

Be it known that I, CLIFFORD D. BABCOCK, a citizen of the "United States,fresiding at New York, in the county of New York and State of New York, have invented. certain new" and useful Improvements in Thermo- Expansion Meters; and I do hereby declare the following to be a full, clear, and exact decuit. Fig. 3, a diagram of a switch a the non-conductin scription of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My'invention relates to a multiple range thermo-expansion meter, and has for its object the production of a hot wire current meter which will be more eflicient than those heretofore proposed, and. which will be capable of a much greater range.

With these objects in view, my invention consists. in the novel combination of parts more fully hereinafter disclosed and particularly. ointed outin the claims. v

Re erring to the accompanying. drawings forming a part of this s ecification in which like numerals refer to ike parts in all the views Figure'1, is a diagrammatic view of my thermo-exp'ansion meter showing the.

multiple scale. Fig. 2, a diagram of a switch connection when onlyone hot wire is in cirwhen the other hot wire is in circuit. Fig. 4, a diaram of another switch connection when %oth' hot wires are joined in series, and Fig. 5, still another diagram of a switch connection 'showin the hot wires j oined in parallel.

1, in icates the source of the current to be measured; 2, a suitable switch in' circuit therewith; .3, a suitable means iorturning said switch; and 4, 5 and 6, different scaleson the scale su port 30, rigid with the turning means 3, an provided with the trunnions 31 and 32, which scales are successively turns into operative positions with respect to the pointer 7, when the switch is turned. 'lhe pointer 7, is mounted on the pivot 8, around which passes the filament 9, which is secured at one end to the spring 10, controlled by th adjustable screw 11, and at the other end to filament 12, whose ends are attached to the expansion measuring wires 13 and 14 respectively. T he wire 13 is secured between the posts 15 and 16, and the wire 14 between the posts 17 and 18.

19, represents a post joined to the posts 16 and 18 hy. the connections 20. 23, 24 an. :25 nt suitable wires joining these posts to Specification of Letters Patent.

Application filed May 21, 1908.

Patented June 29. 1909.

Serial No. 434,148.

the switch 2; and 21 and 22 Wires leading from the source of currenttosaid switch as shown.

There four scales on the scale support 30, of which only three are shown, and each is struck from the pivot Sas a center. The said scale support is preferably of the double conical or lozenge shape shown, but of course may be made of any form and provided with any supports desired.

The particular details of the switch are not illustrated, the'samo do not constitute a .part of the present invention, but any suit anle.sw1tch may be employed, which will make the connections diagrammatically illustrated in Figs. 2, 3, 4i and 5, and at the same time lxring the proper scale intov positionfin relation-to the pointer 7. That is to say, any switch may be employed which,

.when turned to one position, will cut out the measuring expansion wire 14, and include only the measuring wire 13 in'circuit,- as shown in Fig. 2; which, when turned to another position, will exclude the wire 13 and include only the wire 14 in the circuit, as shown in Fig, 3; which, when turned to a third position, will join both of the wires 13 and 14 in circuit in series, as shovm in Fig. 4

and which,when turned to a fourth position,

will join both of said wires in circuit in paral- 101, as shown in Fig. 5, provided the "proper scale is brought into itsproper relation with the pointer at each connection.

The expansion wires 13 and li may be of the same cross sectional area or of different cross sectional areas 'as desired; and they may have the same or ditlercnt coeiiicienls of expansion.

The operation ofmy theruin-expansion meter is r been carefully calibrated, under standard conditions, and with the use of known currents, the scales will indicate the valucoi the currents passing; through the wires 13. and 14 for each ol the connections disclosed. So when an unknown current is to we measured, the switch is turned until a scale lzrought into the position relative to the pointer shown in Fig. 1. The w'.'e 13 or 14, or both, ac-' cording to the particular connection'made, will then grow. hot, expand in length, and buckle to a greater or less degree, as shown in dotted lines, Fig. 1. The tension of the spring 10, through the filament 9, will'take up the slack thus formed in the filament 12 l and at the same time turn the pointer 7 on its pivot to a degree proportional to said slack, which in turn will depend for its value upon the degree of expansion of the particular expansion wire, or wires joined in the circuit. This expansion will likewise in turn depend upon the current passing through said wire or wires, and since the scales have beenempirically marked for lel zown currents,

as above stated, the deflectioh'of the pointer 7' on the scale corresponding to the particular connectlons made by the switch will indicate the value of the current that is passing. It will thus be seen that by employing two expansion wires, I am enabled to get four 1 ranges of readings instead of one, as would be the case if only a single wire was used.

Of course I do not wish to be limited to the exact operation and details of construction above disclosed, since it is obvious that those skilled in the art may vary both without departing from the spirit of my invention.

.What I claim is i 1. In a hot wire current meter, the combination of a plurality of expansion elements; a

l; switch adapted in one position to close a circuit through one of said elements, and in another position to close a circuit through an- .other of said elements; a p l inter; and a scale for each of, said circuits 'with which said pointer coacts, substantially as described.

2. In a hot wire current meter, the combination of a plurality of expansion elements; a switch adapted to close two circuits each of which contains one of said elements and also to'close a third circuit containing both the elements of said first mentioned circuits; a pointer; and a scale for each of said circuits, adapted to be moved by said switch into cooperative relation with said pointer, substantially as described.

3. In a hot wire current meter, the combi- :nation of a lurality of expansion elements which are a apted to form portions at different times of different circuits; a switch adapted to close three of said circuits and I scale for each of said circuits; and a pointer controlled by the expansion of said elements adapted to play over each of said scales, sub..

also to closea fourth circuit including a plurality of said elements in parallel; a scale sun iiort rigid with said switch adapted to be m'oiw'fied thereby and provided with a different stantially as described.

4;. In a hot wire current meter, the combination of a plurality of expansion elements; a switch adapted in one position to close a circuit through one or" said elements, and in anments of said first mentioned circuits; a-

pointer; a scale for each of said circuits adapted to be moved bysaid switchinto cooperative relation with said pointer, a filament connectin said elements; a second filament connecting the first filament and a ivot for said pointer over which said second ament plays, substantially as described.

6. In a hot wire current meter, the combination of a plurality of expansion elements which are ada ted to form portionsat different times of di 'erent circuits; a switch adapted to close three of said circuits and-also to close a fourth circuit including a plurality of said elements in parallel; a scale support rigid with said switch adapted to be moved thereby and provided with a different scale for each of said circuits; a pointer controlled by the expansion of said elements adapted to play over each of said scales, a filament connecting said elements; a second filament connecting the first filament and a pivot for said pointer over which said second filament plays, substantially as described. I

7. In a hot wire current meter, the combination of a' plurality of expansion elements adapted at d1fierent times to bejoined in dif ferent circuits, a filament connecting said elements a second filament connected with the first filament; a pivot over which said second filament plays; a pointer on said ivot; a rotary switch for including said e ements in different relations in said circuits; a scale support, rigid with said switch, carrying a plurality-of scales, one for each circuit, provided with trunnions'; a s ring constantly tending to pull said second ament over said pivot and a screw for'adjusting the tension of said spring, substantiahy as descrlbed.

In testimony whereof, I afiix my signature,

.in presence of two witnesses.

CLIFFORD D. BABCOOK. Witnesses: Moses ELY, JosEPH S. HUNT. 

